The present invention relates to an adjustable load bolt adapter bracket assembly particularly adapted for use with a sway brace in securing a bracing element between a fluid pipeline and a fixed structure to anchor the pipeline to the structure. Sway braces are commonly used in building structures for securing numerous types of fluid supply lines to the structure to brace the lines against damaging movement such as could result from a seismic disturbance. An, example of such a sway brace is found in U.S. Pat. No. 4,697,770. As seen therein, the sway brace secures a fluid supply line to a joist or other building structure by means of an elongated tubular bracing member which is held adjacent one of its ends by the sway brace and is fasten at its other end to the joist by a pair of bolts or other approved fastening members.
Recent changes in building codes have required additional securement of the bracing member to the structure. This has been achieved through the use of an adapter plate having three fastener receiving apertures therein. The plate is positioned over the mounting bracket by which the bracing member is secured to the structure or, in the case of the above patented structure, over the flattened end of the bracing element, such that two of the apertures in the plate are aligned with the apertures in the bracket, leaving the third aperture in the plate in axial alignment with the super imposed apertures of the plate end bracket. Through this configuration three bolts or other securement fasteners can be used to secure the bracing member to the building structure, increasing the strength of the attachment. Alternatively, an adapter plate having four apertures can be employed with the bracket to provide two additional fastener receiving apertures for applications requiring even additional attachment support.
While the use of such adapter plates has heretofore satisfied code requirements, they are subject to relative movement with respect to the brackets in the event of eccentric loading during a seismic disturbance due to the lack of any positive engagement between the plates and the bracket. In addition, as various applications in different areas have different structural strength requirements, an inventory of differently sized adapter plates need to be maintained to provide the desired number of additional fasteners for the particular application. The load bolt adapter bracket assembly of the present invention not only provides the positive engagement between the bracket and plate lacking in the adapter plate/mounting bracket combinations heretofore available, but also eliminates the need to carry an inventory of differently sized adapter plates to accommodate either one or two additional fastening members as required for varying applications.